LM4558 IC is a monolithic integrated chip consisting of two operational amplifiers that belong to the LM series of integrated circuits. Although these two operational amplifiers reside in a single package, but they operate independently of each other. However, both operational amplifiers share the same power rails. The two op-amps have very low noise interference among them which makes LM4558 ideal for use in a number of applications.

LM4558 Pinout

Pin Description

It consists of two operational amplifiers inside a single package.

Operational Amplifier 1

Pin2: Positive Input pin

Pin3: Negative Input pin

Pin1: Output

Operational Amplifier 2

Pin5: Positive Input pin

Pin6: Negative input pin

Pin7: Output pin

Pin8 and 4 are voltage supply pins. Connect these pins to voltage supply and ground.

Features

It provides the following features:

It provides a single supply operation in a range of +5.0 V to +15 V and dual supply range lies in between +15V and -15V.

Consumes very low power which makes it suitable for so many applications

Provides matching phase and gain between the amplifiers

The total power dissipation is 200 mW.

It consists of low noise transistors at the input.

It provides continuous protection against short circuits.

The Common-Mode Rejection Ratio is 80dB.

The IC operates in a range of 0 °C to 70 °C.

Where to use it?

LM4558 IC possesses a wide range of common-mode input voltage and differential voltage. In addition to that, it provides a latch-up free operation. You don’t need to connect external components for frequency compensation. It has a built-in frequency compensation which provides stable operation. These features make this device well suited for amplification processes and voltage follower applications.

How to use it LM4558?

The two op-amps inside the chip can perform two different functions at the same time. As mentioned in the above section, this dual amplifier IC is well suited for voltage following applications. Therefore, we will explain this circuit to understand its working.

Voltage Follower Circuit Example

A voltage follower has nothing to do with amplification. It is just like a buffer and outputs the input value as it is. If the load attached to the output has low resistance, it will draw more current. Here comes the advantage of an operational amplifier.

They provide high impedance due to which load draws a very small amount of current. Due to their high impedance, they do not load down the source connected at the input pin. As the inverting input is directly connected to the output pin without any resistor in between them, that’s why it generates the same input value at the output pin.

Multivibrator Circuit Example

It can produce its own input signal with the help of a resistor and capacitor network connected as feedback between inverting input and output pin. Connect a voltage divider between the non-inverting and output terminal. The circuit will behave as a multivibrator and generates rectangular pulses. Figure (4) shows the circuit of a multivibrator.